As such a brake control apparatus, for example, a brake control apparatus which performs a pre-crash brake assist control and which is one example of a pre-crash safety system is developed (for example, refer to a Patent Literature 1 and a Patent Literature 2). Such a brake control apparatus predicts a collision risk with respect to an obstacle (for example, a leading vehicle) which exists anterior to a vehicle on which this brake control apparatus is equipped. When the collision risk is relatively high, the brake control apparatus performs the pre-crash brake assist control for assisting a brake operation by a driver, in order to avoid a collision in advance.
Especially, the Patent Literature 1 discloses a brake control apparatus which increases a rising rate of a braking force more as a contact possibility with respect to the obstacle which exists anterior to the vehicle is higher. According to the brake control apparatus disclosed in the Patent Literature 1, the contact between the vehicle and the obstacle is effectively avoided, because the braking force is increased rapidly when it is difficult for the vehicle to avoid the contact with the obstacle.
Moreover, the Patent Literature 2 discloses a brake control apparatus which makes a gain which is used when a fluid pressure for the braking (a brake fluid pressure) is decreased smaller than a gain which is used when the fluid pressure for the braking is increased. According to the brake control apparatus disclosed in the Patent Literature 2, a velocity of the vehicle immediately before the stop is appropriately adjusted by delicately adjusting a returning amount of the brake, because the brake fluid pressure in returning the brake changes more slowly than the brake fluid pressure in pressing the brake changes.